Abstract

Praseodymium(Pr3+)-doped fluorotellurite glasses were synthesized and broadband photoluminescence (PL) covering a wavelength range from 1.30 to 1.67 μm was observed under both 488 and 590 nm wavelength excitations. The broadband PL emission is mainly due to the radiative transition from the manifolds Pr3+: 1D2 to 1G4. The PL line-shape, band width, and lifetime were modified by the Pr3+ dopant concentration, and a quantum efficiency as high as 73.7% was achieved with Pr3+ dopant in a low concentration of 0.05 mol%. The good spectroscopic properties were also predicted by the Judd-Ofelt analysis, which indicates a stronger asymmetry and covalent bonding between the Pr3+ sites and the matrix lifgand field. The large stimulated emission cross-section, long measured lifetime, and broad emission bandwidth confirm the potential of the Pr3+-singly doped fluorotellurite glass as broadband luminescence sources for the broadband near-infrared optical amplifications and tunable lasers.

(a) Near-IR PL spectra of Pr3+-doped fluorotellurite glasses under 488 nm wavelength excitation. (b) The FWHM bandwidth of the emissions at different Pr3+ dopant concentration. (c) Normalized PL spectra line-shapes and a comparison of them with the Pr3+: 3F4,3←3H4 absorption band (dotted line) located in this wavelength region. The 1.33 μm emission from the Pr3+: 1G4→3H5 transition is also displayed in Fig. 2(c).

(a) PLE spectra of Pr3+-doped fluorotellurite glass samples monitored at 1480 nm. (b) A comparison of the PLE spectrum and the absorption spectrum with respect to the 590 nm band for the 0.1 mol% Pr3+-doped sample. Inset of (b) shows the absorption/PLE spectra intensity ratio of the 3P0 band to the 1D2 band.